Publication

The PCL Theorem. Transactions cannot be Parallel, Consistent and Live

Rachid Guerraoui, Victor Bushkov, Panagiota Fatourou
2014
Conference Papers

Abstract

We show that it is impossible to design a transactional memory system which ensures parallelism, i.e. transactions do not need to synchronize unless they access the same application objects, while ensuring very little consistency, i.e. a consistency condition, called weak adaptive consistency, introduced here and which is weaker than snapshot isolation, processor consistency, and any other consistency condition stronger than them (such as opacity, serializability, causal serializability, etc.), and very little liveness, i.e. that transactions eventually commit if they run solo.

Official source

https://infoscience.epfl.ch/entities/publication/59394b5b-912f-4d56-beac-0b4069b597b9

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Rachid Guerraoui, Victor Bushkov, Panagiota Fatourou
2014
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/59394b5b-912f-4d56-beac-0b4069b597b9

About this result

Related concepts (11)

Snapshot isolation

In databases, and transaction processing (transaction management), snapshot isolation is a guarantee that all reads made in a transaction will see a consistent snapshot of the database (in practice it reads the last committed values that existed at the time it started), and the transaction itself will successfully commit only if no updates it has made conflict with any concurrent updates made since that snapshot.

Isolation (database systems)

In database systems, isolation determines how transaction integrity is visible to other users and systems. A lower isolation level increases the ability of many users to access the same data at the same time, but increases the number of concurrency effects (such as dirty reads or lost updates) users might encounter. Conversely, a higher isolation level reduces the types of concurrency effects that users may encounter, but requires more system resources and increases the chances that one transaction will block another.

Global serializability

In concurrency control of databases, transaction processing (transaction management), and other transactional distributed applications, global serializability (or modular serializability) is a property of a global schedule of transactions. A global schedule is the unified schedule of all the individual database (and other transactional object) schedules in a multidatabase environment (e.g., federated database).

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